A washer has been known that includes a wastewater heat recovery device configured to exchange heat between supply water supplied for washing and rinsing dishes and other tableware in a washing chamber and wastewater drained from the washing chamber during the washing and rising. Washers including such wastewater heat recovery devices are disclosed in Patent Literature 1 (Japanese Unexamined Patent Publication No. H8-150107) and Patent Literature 2 (Japanese Utility Model Registration No. 3132813), for example. The washers disclosed in Patent Literatures 1 and 2 are each provided with a machine chamber accommodating a device such as a pump below the washing chamber in which dishes and other tableware are washed, and each wastewater heat recovery device described above is provided outside such a machine chamber.